China’s Shanghai Nuclear Engineering Research & Design Institute (SNERDI) has installed the third cylinder ring at unit 3 of the Haiyang NPP in Shandong province creating a cap for the top of the containment building. The steel safety shell is an important part of the nuclear island reactor plant and the third safety barrier to prevent the leakage of radioactive materials, SNERDI said.
The Haiyang NPP hosts two AP1000 reactors (units 1&2) which entered commercial operation in 2018 and 2019 with two CAP1000 reactors (units 3&4) – the Chinese version of the Westinghouse AP1000 – under construction. Construction of Haiyang 4 began in April and first concrete was poured for the nuclear island of Haiyang 3 in July 2022. This marked the official start of construction of the first of two CAP1000 pressurised water reactors planned as Phase II at the site. SNERDI noted that the planned construction period for Haiyang 3&4 was 56 months, with both units scheduled to be fully operational in 2027.
The steel containment vessel of the comprises five modules: the bottom head, first cylinder ring, second cylinder ring, third cylinder ring, and top seal. The third cylinder ring has an inner diameter of almost 40 metres, a height of 11.6 metres and weighs some 660 tonnes. Its installation took just under two hours.
SNERDI said it had adopted a series of technical measures to organise and sort out the prerequisites for the installation, optimise the construction logic, prepare the three-ring modular assembly integration plan, optimise the scaffolding platform in time, and overcome welding difficulties given the low temperature and strong wind in the winter.
The reactor pressure vessel (RPV) weighing 281 tonnes was installed at unit 3 in January. This represented significant progress in the construction of the CAP-1000 reactor unit, which uses a modular construction technology that enables the manufacture of large structural modules in factories. These are then installed on site reducing construction time and improving quality control.
Haiyang nuclear power plant is also the centre of an innovative district heating scheme, which since November has been supplying heat through a 23-kilometer pipeline to the cities of Haiyan and Rushan. According to representatives of the State Energy Investment Corporation (SPIC), the project covers an area of 12.5 million square meters and satisfies the need for a clean warmth of about 400,000 people.
The construction of two CAP1000 reactors at Haiyang NPP (units 3&4), Sanmen NPP (units 3&4) in Zhejiang province and Lufeng NPP in Guangdong province, (units 5&6) was approved by the State Council in April 2022.
Image: The third cylinder ring is hoisted into place at Haiyang 3 (courtesy of SNERDI)
